The focus f this proposal is to develop methods to detect, evaluate and understand the toxicity of hazardous substances tin the environment of dump sites and to enhance the utility of bacterial degradation as a procedure to reduce the amount and toxicity of hazardous substances. This focus takes advantage of our existing research strengths in toxicology, environmental microbiology, analytical chemistry, environmental engineering and hydrology. We seek to understand the chemical species which migrate from a site and which are formed based on interactions with bacteria. The characterization of these chemical species will require cooperation between projects in hydrology and chemistry, particularly in the development of selective and sensitive analyses to quantitate both metal and organic species. The results from these studies will be used to quide the toxicology experiments. Basic reseach is proposed to determine interactive toxicity between metal(loid)s and between important organic species and the inorganics. This is coordinated with a project to evaluate the important cellular mechanisms to detoxify these metal(loid)s and important factors which modify these mechanisms. Additional projects investigate immune and teratogenic responses to environmental contaminants. Projects to enhance the utility of bacteria to remediate or reduce the toxicity of environmental toxicity are proposed. The degredation of halogenated hydrocarbons and the bacteria which can accomplish these reactions are to be examined. The movement of bacteria are important in understanding bacterial distribution and in planning how beneficial bacteria could be effectively applied to a contaminated site. This will be studied in addition to site treatment schemes which enhance the rates of bacterial degredation of hazardous dumpsite chemicals.